1. Field of the Invention
The present invention relates to a copying machine and, more particularly, to a copying machine with an automatic document feeder which exhausts an original in sheet form after passing it over an exposing part while holding it on a cylindrical holding drum.
2. Description of the Prior Art
Copying machines of higher speed and automated sequences are in more demand with the recent need for higher efficiency in office work. On the other hand, it is also desired that the copying machines and various other related equipment be simplified in construction.
Various automatic document feeders (ADF) are conventionally used for automatic feeding of an original. In particular, an automatic document feeder which is used in a mounted position on the copying machine from which an original press plate is removed requires more space and is heavier in weight. With a so-called circulation-type automatic document feeder, since the original is carried over a long distance several times, the original may become damaged and jamming tends to occur.
With a conventional copying machine with an automatic document feeder of the type described above, the feed timings of an original and a copy sheet are synchronized by, for example, counting drum clocks which are generated upon rotation of a photosensitive drum. Due to the reading error of pulses generated in response to the clock pulses, it is difficult to attain high precision in synchronizing the feed timings of the original and the copy sheet and to achieve a desired reliability.